Apparatus for packaging finely divided materials



Sept. 17, 1963 E. s. WOLLETT APPARATUS FOR PACKAGING FINELY DIVIDED MATERIALS Original Filed Oct. 12, 1956 2 Sheets-Sheet l V. N {2 I y n K. V a" M T1 0 v a w z a A x -T ,Z, J 3 we fzrrrrllfiltlfrzll INVENTOR ATTORNEY Sept. 17, 1963 E. s. WOLLETT 3,103,698

APPARATUS FOR PACKAGING FINELY DIVIDED MATERIALS Original Filed Oct. 12, 1956 2 Sheets-Sheet 2 g 1 /5 7D $544 mm 176?.16672. nsvrcawx.

30K c/a lN VENT OR ERA/5725 44577;

BY d" ATTORNEY United States Patent 3,143,698 APPARATUS; FOR PACKAGING FiNlELY DEVKDED MATERIALS Ernest S. Wollett, Washington, D.C., assignor of two-thirds to S. G. Leoiiier Griginal application Oct. 12, 1956, Ser. No. 615,651, new Patent No. 2,9593%), dated Nov. 15, 1960. Divided and this application Aug. 5, 1960, Ser. No. 56,978 2 Qlairns. (Cl. 18--5) This invention relates to the packaging of finely divided materials that must be readily reducible again to the finely divided condition, and aims generally to improve the same. More particularly, the invention relates to the packaging of such materials in the form of compacted rectangular blocks of substantial size, and more especially to the compacting of clay powder into rectangular blocks of, say, fifty pound size, in a minimum of space commensurate with the ability of the clay to freely return to its powdered form for use as fillers in rubber manufacture, or for use of the ceramics industry, or the like.

Clay, flour, and like finely divided goods, have heretofore been shipped principally in bags, or boxes. Such goods contain large quantities of air, and do not readily settle into a compact form, even when subjected to vibration or shaking. Hence the boxes or bags have had to be correspondingly large because of the inherent bulk of the product, and of relatively heavy stock to resist puncture and lossof the powdered material. When an effort is made to mechanically compress such materials, the entrapped air is also compressed, and on release of the mechanical pressure, expands and ruptures the block. Attempts to pack such materials under vacuum have also not been successful because of the difiiculty of screening against loss of the material, clogging of screens, and inability to scavenge the entrapped air from deep bodies of the material.

The present invention aims to overcome disadvantages attendant on prior methods of packing such materials, and to provide a new method and apparatus for producing a compacted but readily decompacted block from such materials, preferably rectangular, and preferably closely wrapped with paper or other wrapping material that is supported by the denseness of the compacted material, thus minimizing puncturing of the wrapper in handling and allowing lighter packaging to be used, and

that in turn holds in place any sections of the block that may be cracked off by rough handling, thus to maintain the Weight and shape of the packed goods.

With these general aims in mind, the invention has for particular objects, severally and interdependently, the provision of a novel method of compacting clay and like finely divided materials into form retaining but readily disintegratable blocks; the provision of new apparatus constructed to facilitate the practice of the novel method; the provision of a method and apparatus that enables the compacted block to be formed and handled during wrapping on the wrapper material acting like a pallet; and the provision of a new wrapped product adapted to be stacked and handled in a minimum of shipping and storage space for the weight of the product commensurate with its being returnable to its finely divided form.

The invention also aims to provide new and useful subsidiary steps and features and subcombinations thereof contributing to the realization of the general objects of the invention.

The invention itself resides in the new methods and means for forming the blocks of finely divided material, in the successfully compacted blocks thereof, and in subordinate steps and elements thereof, as hereinafter exemplified, and is more particularly pointed out in the appended claims. .The present application is a division of my copending application Ser. No. 615,651, filed Oct. 12, 1956, now Patent 2,959,900 of Nov. 15, 1960, relates to the apparatus therein disclosed, and has been filed pursuant to a requirement for restriction in said copending application, wherein the method aspects of the invention are claimed. The product aspects of the invention have been made the subject of a separate application pursuant to said requirement for restriction.

In the accompanying drawings illustrating various features of the invention:

FIG. 1 is a more or less diagrammatic elevation partly in section, of an apparatus for packaging clay in accordance with and by the method of the invention, and FIG. 1a is an enlarged sectional detail of a portion thereof.

FIG. 2 is a similar view of apparatus that may be associated with the apparatus of FIG. 1.

FIG. 3 is a diagrammatic view of a conventional hydraulic system employable with the apparatus of FIG. 1.

FlG. 4 is a perspective view of a sealed packaged block of dry finely divided material according to the invention.

FIG. 5 is a schematic diagram of means for' automatically controlling the operation of the machine for the carrying out of the method.

Finely divided clay in bulk is so highly aerated and fiulfy that a weight of fifty pounds of it occupies a volume of about 2974 cubic inches, i.e. a depth of about 14 inches in a 12 inch by 18 inch rectangular container (216 square inch cross section). Shaking can only reduce the volume slightly, and when an attempt is made to mechanically compress the height of the body in a sealed container, the air entrapped in the clay is compressed, and re-expands when the pressure is removed, causing disintegration of the body. When attempts are made to exhaust air as the loose clay body is mechanically compressed, much finely divided material is lost, screens are clogged, and since the clay compacts quite densely against the compacting piston, but is more and more highly aerated as the distance from the piston (and consequently the depth of clay through which air must escape) increases, only a limited amount of the air content can be Withdrawn, with the result that attempts to form blocks of clay, and like finely divided aerated materials, by the application of mechanical pressure and vacuum, per se, have been unable to yield satisfactory form retaining blocks.

The present invention, however, effects a new rnethodof compacting such finely divided clay, herein takenas representative of clay and finely divided materials in general, 'by initially only partially compacting the clay mechanically'in a sealed mold; then breaking down or subdividing the compacted layer of clay just ahead of the compacting piston and providing air escape channels therein while maintaining the clay under pressure; then venting the air pressure through the channels so provided; and then evacuating residual air through such channels while comp-acting the clay from its initial partly compacted condition to its final condition as a self sustaining block, the initial compacting and channelling avoiding undue carry-out of finely divided clay during these latter steps.

In a typical example of the compacting of Tennessee kaolin into fifty pound blocks of 12 inch by 18 inches cross section by the present invention, when the finely divided substantially dry clay is dumped into the mold cavity, it is usually sloped at an angle of repose, but in a of the piston tends to evenly or flatly distribute the flowable clay in the mold cavity and solidify it enough so that its fiowability is reduced. This initial partial compacting of the clay may reduce the depth of the bulk clay body from about 14 inches to about 9 inches. Since the mold is kept sealed during this initial compacting loss of clay from the mold is prevented and the pressure of the air within it is raised'from about 1 atmosphere to abut 2 to 3 atmospheres. As the clay packs just ahead of the piston,

the air expressed from it moves toward the bottom of the mold, increasing the pressure of the air thereat without compacting very much the clay remote from the piston.

If now an attempt is made to vent or exhaust the air from the partially compacted block in this condition, first, the time required for passage of the compressed air from the lower parts of the mold through the partially compacted area of clay ahead of the piston is excessive;

second, the tight packing of the clay across any vent port or screened vent port, clogs the same; third, if the piston is raised to relieve the pressure, the expansion of the entrapped air reverses the partial compacting of the clay; and fourth the expansion of such air carries excessive quantities of finely divided clay through the vent or exhaust openings.

But 'by admitting more compressed air to the mold, the present invention, peculiarly, largely eliminates these difficulties. Preferably this added compressed air is admitted through a screened opening in the center of the piston and may be quite large (equivalent to an opening nearly an inch in diameter, when the 12 x 18" piston has a clearance of only .005 from the sides of the mold), very little air-borne clay is carried past the piston during the initial evacuation.

When the vacuum has built up enough in the mold (substantially full vacuum can be reached in a fraction of a second) the piston is again advanced, while maintaining the vacuum, to decrease the height of the mold cavity, in the typical example, from about 9" to about 5% inches, thus to compress the clay, that originally occupied about 29-74 cubic inches, into a block having a volume of only about 1115 cubic inches or about Vs of its original volume.

This degree of compacting is attained with a pressure of about 2 00 lbs. per square inch on the clay, and even if such pressure is raised by 50% or more, say to 320 lbs. per square inch, substantially no further reduction in the height of the block can be obtained.

In the preferred practice of the method, the compacted block is formed on a sheet of paper, or on the leading portion from a roll of paper, which is placed between the mold bottom and mold walls, and sealed to the latter during the molding operation, and which is employed to move the block and for wrapping the same.

In the typical example, when the upper piston has advanced to the final compacting position, the pressure supporting the mold bottom is reduced to a point at which it is just sufficient to hold the mold bottom (and paper when present) up against the block. The piston is then further advanced, as the mold bottom is lowered and gently pushes the block and the mold bottom ahead of it until the block is completely out of the mold cavity.

1 Then further lowering force is applied to lower the mold bodies with air collecting spaces or venting channels relatively free of clay between them. In the typical example,

with about 2 to 3 atmospheres pressure in the mold (say 29 pounds per square inch, gauge), the added air may he suddenly admitted at a pressure of about 4 to 5 atmospheres, say 60 pounds per square inch gauge. The air preferably through the central screened piston opening through which the compressed air was admitted. This mode of venting is deemed particularly desirable, as the rapid fiow of highly compressed air from the clay through the relatively clay-free fissures :or channels therein carries most of the air-borne fines from the clay body toward the crater formed by the impinging compressed air, where they are retained by the screen. Because the fissures and crater are relatively free of. clay, the airborne clay carried to the screen is not sufiicient to clog it, and is of course displaced from the filter by the next air jetting operation.

When the pressure in the clay has been reduced substantially to atmospheric pressure in this way, which may require a half second or so, the marginal seal of the piston against the walls of the mold is opened, and a vacuum reservoir, containing a vacuum measured at 20 to inches of mercury in the typical example, is connected to the space above the thus opened margins of the piston. The application of this vacuum causes further air to be evacuated from the body of the clay through the channels previously mentioned in a generally outward radial direction to the margins of the mold. Since the pressure difference is less than that occurring in the initial venting operation; since the clay is well compacted near the outer walls of the mold; since the venting has already carried most of the air-borne fines to the central part of the body; and since the opening about the piston bottom and block until the top of the block is about 2% inches below the lower edge of the mold box, at which point the leading ends of the lateral edges of the paper, if present, are disposed on top of a movable carrier,

to which the paper may be gripped in any suitable manner so that it and the block may be pulled from the molding press to a wrapping zone at which the sheet of paper, cut to the proper length, may be wrapped snugly about the block and sealed, either manually or mechanically.

As above noted, the combination of steps by which the clay is compacted, and especially the jetting of the fissur in'g air into the top central portion of the block, tends to partly concentrate the clay against the side walls of the box, so that if during the mechanical pressing, any soft spot does remain, it will generally occur at the top center of the block where it will not cause crumbling of the side walls and corners of the block during wrapping. When the block is snugly wrapped, the high density of i the clay supports the wrapper against puncturing, and

even if a part of the block cnacks off within the wrapper, the wrapper holds it in place, maintaining the shape and true weight of the package.

Further, when the clay is to be employed as a filler in l the manufacture of rubber or plastic goods, the wrapper maybe formed of a plastomer film or sheet that is compatible with and soluble in the material to be filled, and the entire package may be added as a measured quantity in the mill or mixer. Similarly when hour or the like is being packaged, the wrapper can be either of paper, and be removed, or of a soluble gelatin film or the like, that may be incorporated in the bread or cake mix without deleterious eifect on the product to be prepared.

A preferred apparatus according to the present invention, as illustrated in FIG. 1, comprises a frame 10pmportioned to sustain the weights of the parts and ,the hydraulic pressures employed for mechanically compacting the clay. Such frame, in the form shown comprises abase plate 10a, vertical tension supporting columns 1011, at the corners thereof, supporting sleeves 1G0 surrounding the lower portions of such columns, a mold box support- 5 ing frame lit-d positioned by the columns 10b and supported by the sleeves 10c and a piston supporting platform itlf carried by the upper ends of columns 1%.

The mold box 11, which for purposes of illustration, may be considered as rectangular and of :a cross section of 12" x 18" with a height of 14" or more, in the form shown comprises a positioning flange 11a that rests on top of the marginal supporting frame 10d, and which may be notched at its corners to fit around the column lob, as shown. The lower edge of the mold box, in the form shown, lies substantially flush with, or slightly below, the under surface of the mold supporting frame 10d, and is provided with a sealing gasket 11 of rubber or other suitable material.

The mold bottom, in the form shown, comprises a platform 12, movable vertically by controllable means such as a conventional hydraulic system of suitable capacity, comprising the hydraulic piston 12a that travels in a hydraulic cylinder 12b, packed at 12c about shaft 12d and provided with elevating and lowering chambers Hi and 12g, to and from which fluid under pressure, preferably hydraulic fluid, may be supplied from a suitable pressure pump and exhausted to a suitable reservoir, as by a dual 3-way control valve 12h that may be perated manually, or by remote control, or by suitable timing or limit control apparatus, as will be understood by those skilled in the art. For the purposes of the present invention, the system is further provided with a hy-pass comprising a stop valve 12k and a constant pressure maintaining relief valve 12m, that is adjusted to just balance the weight of the piston and platform 12, 12a, 12d with the weight of the compressed block thereon, so that a very slight pressure on the top of this block will produce downward floating of the system.

The mold bottom, in the form shown, contacts the sealing ring 11b of the mold box (with the paper sheet, hereinafter described, intervening) and may contact the mold supporting rim l ed at the upper limit of its stroke. When lowered, the upper surface of the mold bottom 12 aligns with a take-away platform 13 (about 8" below the bottom of the mold box 11 where a block about high is to be formed). At either side of the platform 13, in the form shown, travelling carriers 14 are provided, that are adapted to be moved longitudinally away from the machine by any suitable means, that may be control-ledmanually, by limit switches correlated with the lowered and raised positions of the mold bottom 12, or otherwise. Suitable grippers 15, illustrated :as jaws drawn downwardly and inwardly toward the carriers 14 by solenoids 16 against the action of springs (not shown), are provided for gripping the margins of the paper sheet 17 to the carriers 14- when the mold bottom 12, sheet and block are in lowered position, for drawing the block from the mold bottom 12 onto the take away platform 13, using the paper sheet 17 as a pallet for this purpose. The paper sheet 17 may be drawn from a continuous roll 17a, mounted in any suitable position, and is of a width (say 24" for a block 18 wide and 5% thick) that will enable it to be folded over the ends of the block after being wrapped around it, with enough overlap for sealing, as with a strip of heat-sealing resin impregnated paper tape, for example. Such strips of tape may be ap plied manually, or in the wrapping machine (which per se forms no part of the present invention) or may be applied to the under sides of the leading edge and the marginal edges of the sheet while it is gripped between the mold bottom 12 and mold box 11, if desired. When the paper 17 is drawn from a roll 17a, as shown, means is provided for cutting a proper length of sheet from the roll, as exemplified by the shear blade 18 in FIG. 1, which may be operated manually, or by a limit switch, when the carriers 14 have drawn out the sheet the required distance, say 35 or 36 inches where the block is to be 12 inches long by 5% inches thick by 18 inches riers 14.

As above mentioned, when the paper sheet 17 is used,

as is preferred, it passes between the mold bottom 12 and the lower end of the mold box 11, is pressed against the gasket 11b by the mold bottom, in the position indicated by the dotted line 17 in FIG. 1, and is lowered with the mold bottom 12 to lay its leading edge on the platform 13 and carriers 14 between the grippers 15 that are then operated to grip the paper to the carriers 14 for movement therewith.

The means provided for loading a measured quantity of clay or the like into the mold box 11 may be of any suitable form, and is herein exemplified by a hopper 20 for receiving the dry, powdered clay, provided with a suitable feeder or agitator 21, and with a cut-off shutter 22, herein shown as integral with the weighing box 23 that rests on the platform 24 of a scales 25 the beam of which rises when the measured quantity of clay is added to the tare-weight of the parts. The weighing box 23 and shutter 22 are moved from the scale platform 24- across a feed platform 26 until the box 23 aligns with the mold box 11 to dump its contents therein. Such motion may be effected manually, but is preferably effected by a hydraulic ram 27, of conventional construction, the valves of which are actuated inter alia, by a trip switch controlled by the scale beam for advancing the ram, and by a limit switch actuated when the box 23 reaches its idle position on the platform 26, which limit switch is bypassed when the clay is to be dumped, causing the ram 27 to move the box 23 to its full dump position. After dumping the cycle of the loading mechanism retracts the box 23 to its filling position, and the scale beam operated limit switch advances it to its idle position when it has been refilled. Alternatively, the beam controlled switch may stop the hopper feed means 21, and the ram may be controlled by trip switches correlated with the end of the compacting cycle of the machine or with the rising operation of the mold bottom 12 to move the weighing box to its dumping position directly from the filling position. And when the average density of the aerated material is sufliciently constant, the box 23 may simply accommodate a predetermined volume of the material, the scales may be dispensed with, and the box 23 may be retained in the position shown, or moved to the platform 26, as desired, after it is filled.

The compacting piston 30, in the form shown, is carried, by the piston rod 30a of a hydraulic device 30b, per se of conventional form, that comprises lowering and lifting pressure chambers 30c and 3% with travelling piston 30 and fluid inlet and relief lines 30g, 3% controlled by dual 3-way pressure inlet and relief valve means 30k that may be operated manually or automatically, as by solenoid means actuated by trip switches associated with the retraction of the weighing box 23 from the compacting machine, by timing means, or otherwise. As is conventional, the hydraulic inlet and outlet lines A and B of the valves 12h and 30k are preferably connected directly to the constant-pressure output and return lines A and B, respectively, of the pressure system (FIG. 3) that may comprise reservoir R, pump 12R and constant pressure by-pass 12t, as shown. 7

The piston rod 30a has packed passage through both heads of the cylinder 30d, 30c and is traversed internally by two pneumatic fluid conduits 31 and 32. Theflconduit 31 communicates with a pneumatically expansible gasket 33, adapted when inflated to project from a peripheral groove in the piston 3% into sealing engagement'with the walls of the mold box 11 (see FIGS. 1 and la),and when deflated to afford clearance between piston 30 and said walls, that may be of the order of .005 inch where clay is being packed in 50 lbs., 12 x 18 x 5%blocks.

The conduit 32 communicates with a central recess 34 in the center of the piston head, that is covered with a a screen or filter cloth 35, about 2" in diameter in the case just mentioned.

A mold cap or head 36 is slidably mounted on the piston rod 30:: (the joint being packed as shown) and is provided at its lower end with a sealing gasket 36a for sealingly engaging the upper end of the mold box 11. Suitable means, illustrated as sliding guide ears 36b are provided for guiding the mold cap and piston into accurate alignment with the mold box 11. The interior of the mold cap 36 communicates through a flexible conduit 36:: with a vacuum and relief valve of suitable construction.

The pneumatic pressure and relief valves associated with lines 31 and 32 (not shown) may be of any suitable construction, say 3-way valves. The vacuum and relief valve and systems associated with the conduit 36c may also be of any suitable construction, and may embody suitable means for separating the airborne clay from the evacuated air before it reaches the vacuum reservoir. For example, as indicated in FIG. 2, the vacuum conduit 360 may pass to a central dust separating tube 37 that communicates at its top through a cloth filter 37a with a vacuum line 3-3 having a vacuum valve 39 operated by a solenoid G1, that may be associated with the hydraulic system for timing, and thence communicating with the vacuum reservoir in which a vacuum of from to 29 inches of mercury (preferably about 25 inches) of mercury is maintained.

The lower end of the dust separating tube 37 may be closed by a flap valve 37b pivoted at 37c and suitably operated, as by a solenoid G2 that may be similarly associated. The outer housing 37; may communicate at its bottom with a fan 41 or other removal device for transferring the clay dust to a suitable collector or receiver.

As will be evident from the description of the novel method, the sequencing of the several operations of the machine to carry the method into effect may be controlled manually, or by timer means, or each step of the operation may be controlled in response to completion of the prerequisite step, or the system may be controlled by any combination of such modes of operation. Merely for clarity, and without limiting the invention thereto, one mode of controlling the operation will now be set forth with reference to FIGS. 1 and 5, by way of example:

At the outset, the wrapping sheet 17 will be positioned in the machine; the charging box 23 will be filled with the charge of finely divided pulverulent material; valves 1211, 39k and 2712 may be at neutral or hold position with the piston 12:: at the bottom of its stroke, piston 3th at the top of its stroke and piston 27a stopped at the center of its stroke.

Referring to box A, FIG. 5, the closing of starting contacts A1 may energize stick-solenoid A2 from power source P to move valve 12h, biased to hold position as by a spring means 12x, to position R for raising the mold bottom 12, which, on approaching the top of its stroke, for an interval closes contacts A3 that energize the loader advancing stick-solenoid B1 (box B) initiating the loading cycle.

The solenoid B1 (box B) moves valve 27b from hold to advance A moving charging box 23 from its idle position on 26 (FIG. 1) to dumping position, allowing contacts B2 to close in the stick-circuit of solenoid B1 before contacts A3 are released. At dumping position a partmoving with box 23 opens contacts B3 deencrgizing solenoid B1 and returning valve 27b to neutral position; and simultaneously contacts B4 are closed, energizing stick-solenoid B5 that moves valve 27b to retract position R to draw box 23 to its filling position.

As soon as box 23 is drawn back onto platform 26 a part moving with box 23 momentarily closes contacts B6 to initiate operation of piston 36 as hereinafter described in connection with box C. As box 23 reaches its filling position it opens contacts B7 in the stick circuit of relay B5 allowing valve 271: to return to hold position H. When the weight of clay delivered to the box 23 operates scales 24 these scales close restart contacts B8 in the pilot circuit of advance solenoid B1, and the box 23 is moved back onto platform 26 at which point a part associated with box 23 opens contacts B2 in the stickcircuit of solenoid B1, terminating the loading and filling cycle.

When the retraction of box 23 closes contacts B6, stick-solenoid C1 is energized moving valve 39!: from its hold position H to position L to lower piston 30. A part moving with piston 30 closes contacts C2 as soon as the piston 36 enters the mold box 11, to energize stick solenoid D1 to move valve 31a from its vent position V to its sealing position S and inflate seal 33 through conduit 31.

Following the inflation of seal 33, piston 36 continues to lower until it has compressed the aerated clay to a depth of say, 9 inches, at which point contacts C3 are opened to break the stick-cireuit C1 and allow valve 36/: to return to its position H to stop piston 39 at that point. Simultaneously, contacts C4 are closed to initiate the airjetting and venting cycle that will now be described.

The closing of contacts C4 energizes stick-solenoid E1, that moves valve 32:: from its closed position C to its jet position J, admitting jetting air through line 32 (FIG. l) to channel the initially compacted clay. Differential pressure operated device 321), when the static pressure in conduit 32 becomes equal to that entering valve 321:, operates to open contacts E2 and close contacts E3 to deenergize solenoid E1 and energize solenoid E4, thus moving valve 32a to vent position V.

The differential pressure operated device 320 (box F) having :been retracted when the pressure in conduit 32 became greater than atmospheric, again advances when that pressure becomes substantially equal to atmospheric, and a part moved thereby then momentarily opens contacts F1 in the stick-circuit of solenoid D1, to release that solenoid and return valve 31a to its vent position V, thus deflating the seal 33.

At the same time device 320 momentarily opens contacts F2, in the stick-circuit of solenoid E4, thus releasing that solenoid and returning valve 32a to its closed position to ready the mold for the application of vacuum to its interior.

Following the deflation of the seal 33 and closing of the jet-and-vent conduit 32, the device 320 (box F) closes contacts F3 for initiating evacuation of the mold by energizing stick solenoid G1 and parallel solenoid G2 (box G) to open vacuum valve 39 and close vent valve 37b, also shown in FIG. 2.

The differential pressure device 36g operates when the vacuum in conduit 36c becomes substantially equal to that entering valve 39, and closes contacts G3 to reenergize stick-solenoid C1 and re-start downward motion of the piston 30 for the second stage of compacting. When the second compacting is completed, a part moving with piston 30 opens contacts C5, which are in the stick circuit of solenoid G1, thus closing the vacuum valve 39 and opening the vacuum venting valve 37b. Contacts CSa in this stick circuit of solenoid C1 may be opened simultaneously with contacts C5, to stop the descent of piston 36 at this point if desired, or such circuit breaking contacts may be omitted, in which case contacts G7 (hereinafter described) may also be omitted.

The difierential pressure device 3611 (box G and FIG. 2) having been retracted when the pressure in conduit 36: became substantially less than atmospheric, operates as such pressure returns to approximately atmospheric,

momentarily opens contacts G4 in the stick circuit of solenoid A2, thereby returning valve 1212 to its hold position H, momentarily closes contacts G5 to energize sticksolenoid G6, to open the by-pass stop valve 12k and thus unlock the mold bottom 12 so that it can be lowered by pressure on its top surface, and momentarily closes contacts G7 to re-energize solenoid C1 and restart lowering of piston 30.

When piston 30 has pushed the block clear of the bottom of the mold box 11, parts moving with it close contacts C6, energizing mold bottom lowering sticksolenoid A4, and momentarily open contacts C7 in the stick-circuit of solenoid G6 to close the by-pass stop valve 12k, thus initiating positive lowering of the mold bottom 12 to move the block well clear of the mold box 11, and also momentarily close contacts C8 and open contacts C9 for energizing stick-solenoid C10 and deenergizing solenoid C1 to initiate upward motion of piston 30, that proceeds until piston 30 reaches its upper limit, when a part moving with it opens contacts C11 in the sticlocircuit of solenoid C10, de-energizing it and returning valve 30k to its hold position H.

When the mold bottom 12, started downwardly by closing of contacts C6, reaches alignment with the platform 13, a part moving with it opens contacts A in the stick circuit of solenoid A4, allowing valve 1211 to return to its hold position H to terminate the lowering, and closes contacts A6 to energize stick-solenoid J1 and parallel solenoid means J2 (also shown in FIG. 1). Solenoid J1 moves a valve J3, similar to valve 12h, from its hold position H to its drive position D, and solenoid means J2 actuates grippers 15 (FIG. 1) to grip the edges of the sheet 17 to the carrier means 14. The moving of valve J3 to position D initiates drive of the carrier means 14 to draw the sheet 17 and the block carried by it outwardly across the platform 13 toward the Wrapping zone. When such motion has drawn the block clear of the compacting machine, and far enough in the preferred embodiment to draw past cutter 18 a sufficient length of paper 17 with which to wrap the block (36 inches in the case assumed for illustration), a part moving with the carriers 14 opens contacts J5 in the. stick circuit of solenoids i1 and J2 and closes contacts J4 and 16. The closing of J4 energizes cutter operating stick solenoid K1 to operate the cutter 18 to sever the sheet 17; the opening of J5 de-energizes stick solenoids J1 and J2, terminating the driving motion of carriers 14 and releasing grippers 15; and the closing of contacts J6 energizes stick solenoid J7, moving valve J3 to its reverse position R and initiating return of the carriers 14 to their initial position (FIG. 1) at which a part moving therewith opens con tacts J8 in the stick circuit of solenoid J7 to allow the valve J3 to return to its hold position H to stop the motion of the carriers 14.

On operation of the cutter 1.8 by stick-solenoid Ki contacts K2 in the stick circuit of solenoid K1 are opened, and contacts K3 and K4 are momentarily closed. K2 as shown, releases the cutter operating solenoid and allows the cutter to return to its open position to which it may be biased, as by a spring K5. Contacts K3 may initiate operation of the wrapping machine, and contacts K4 may apply power to the pilot circuit of stick solenoid A2 in parallel with the starter button A1, to automatically restart the loading and block forming cycle now fully described.

The wrapping of the block, as above noted, may be eflected either manually, or by automatic machine. In either case, as shown in FIG. 4, the sheet 17 of paper, water-resistant paper, or film compatible with intended use, is preferably folded about the block with its foreand-aft edges overlapped as shown, and with a sealing strip 17a applied over the exposed portions at the outer superimposed edge, the ends being then folded as shown, with a sealing strip 1712 applied on the lapped edges at each end as shown, although any other mode of covering the block may be employed within the broader aspects of the invention.

Where the mold box 11 and piston 30 have been referred to herein as rectangular in cross-section it is to be understood that the corners of the mold box and of the piston may be filleted or rounded on a suitable radius, say 4 inch for a package 12 by 18 inches in cross-section, to facilitate tight sealing of the expansible seal 33 and avoid undue fragility at the edges and corners of the block.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come Within the meaning and range of equivalency of the claims are intended to be included therein.

I claim: I

1. Apparatus for compacting finely divided material, comprising a mold box having a movable bottom and a top piston, means for closing the bottom against the mold box, means for advancing the top piston into the mold box for compacting material deposited therein, means for delivering between said movable bottom and said mold -boxto be clamped therebetween during the depositing of the material in the mold box and the subsequent compacting of the material therein-a sheet of wrapping material of a size suitable for wrapping the body of material being compacted thereon; means operatively connected with said movable bottom and top piston for simultaneously lowering the movable bottom, the paper sheet the compacted material and the top piston relative to said mold box, thereby to remove the compacted material from said mold box on said paper sheet; and means operatively connected with said movable bottom and top piston for thereafter relatively displacing said top piston and the paper sheet carrying said compacted material for enabling said compacted material to be enclosed within said paper sheet.

2. Apparatus according to claim 1, further comprising means for injecting compressed air into said mold box, a mold cap embracing and slidably related to said piston, said mold cap adapted to sealingly engage the top of said mold box, and conduit means for additionally applying a vacuum to the interior of said mold cap during the injection of air into said mold box.

References Cited in the file of this patent UNITED STATES PATENTS 399,064 McLean Mar. 5, 1889 764,361 Jaques July 5, 1904 783,516 Goodwin Feb. 28, 1905 2,026,940 Hendryx Jan. 7, 1936 2,301,939 Fischer Nov. 17, 1942 2,376,003 Palmer May 15, 1945 2,449,257 Tucker Sept. 14, 1948 2,586,148 Clark et a1. Feb. 19, 1952 2,720,737 Vogt Oct. 15, 1955 2,814,921 Beerend Dec. 3, 1957 2,856,667 Gorsuch Oct. 21, 1958 2,867,844 Hall Jan. 13, 1959 2,876,492 Frieder et a1. Mar. 10, 1959 2,886,849 Brierley May 19, 1959 FOREIGN PATENTS 113,858 Netherlands Apr. 17, 1945 705,955 Great Britain Mar. 24, 1954 

1. APPARATUS FOR COMPACTING FINELY DIVIDED MATERIAL, COMPRISING A MOLD BOX HAVING A MOVABLE BOTTOM AND A TOP PISTON, MEANS FOR CLOSING THE BOTTOM AGAINST THE MOLD BOX, MEANS FOR ADVANCING THE TOP PISTON INTO THE MOLD BOX FOR COMPACTING MATERIAL DEPOSITED THEREIN, MEANS FOR DELIVERING BETWEEN SAID MOVABLE BOTTOM AND SAID MOLD BOX--TO BE CLAMPED THEREBETWEEN DURING THE DEPOSITING OF THE MATERIAL IN THE MOLD BOX AND THE SUBSEQUENT COMPACTING OF THE MATERIAL THEREIN--A SHEET OF WRAPPING MATERIAL OF A SIZE SUITABLE FOR WRAPPING THE BODY OF MATERIAL BEING COMPACTED THEREON; MEANS OPERATIVELY CONNECTED WITH SAID MOVABLE BOTTOM AND TOP PISTON FOR SIMULTANEOUSLY LOWERING THE MOVABLE BOTTOM, THE PAPER SHEET, THE COMPACTED MATERIAL AND THE TOP PISTON RELATIVE TO SAID MOLD BOX, THEREBY TO REMOVE THE COMPACTED MATERIAL FROM SAID MOLD BOX ON SAID PAPER SHEET; AND MEANS OPERATIVELY CONNECTED WITH SAID MOVABLE BOTTOM AND TOP PISTON FOR THEREAFTER RELATIVELY DISPLACING SAID TOP PISTON AND THE 